Patents by Inventor Alexandros Tourapis

Alexandros Tourapis has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 11282238
    Abstract: A system comprises an encoder configured to compress attribute information and/or spatial for a point cloud and/or a decoder configured to decompress compressed attribute and/or spatial information for the point cloud. To compress the attribute and/or spatial information, the encoder is configured to convert a point cloud into an image based representation. Also, the decoder is configured to generate a decompressed point cloud based on an image based representation of a point cloud. The encoder is configured project the point cloud on to patch planes to compress the point cloud, and supports multiple layered patch planes. For example, some point clouds may have a depth, and points at different depths may be assigned to different layered patch planes.
    Type: Grant
    Filed: September 25, 2020
    Date of Patent: March 22, 2022
    Assignee: Apple Inc.
    Inventors: Khaled Mammou, Yeping Su, David W. Singer, Alexandros Tourapis, Fabrice A. Robinet, Hsi-Jung Wu
  • Patent number: 11284091
    Abstract: A system comprises an encoder configured to compress attribute information and/or spatial for a point cloud and/or a decoder configured to decompress compressed attribute and/or spatial information for the point cloud. To compress the attribute and/or spatial information, the encoder is configured to convert a point cloud into an image based representation. Also, the decoder is configured to generate a decompressed point cloud based on an image based representation of a point cloud. The encoder generates an occupancy map and may adjust a size or placement of a patch in the occupancy map to reduce or eliminate redundant points caused by down-sampling and up-sampling of the occupancy map.
    Type: Grant
    Filed: January 7, 2020
    Date of Patent: March 22, 2022
    Assignee: Apple Inc.
    Inventors: Alexandros Tourapis, Khaled Mammou, Jungsun Kim
  • Patent number: 11284110
    Abstract: Sampled data is packaged in checkerboard format for encoding and decoding. The sampled data may be quincunx sampled multi-image video data (e.g., 3D video or a multi-program stream), and the data may also be divided into sub-images of each image which are then multiplexed, or interleaved, in frames of a video stream to be encoded and then decoded using a standardized video encoder. A system for viewing may utilize a standard video decoder and a formatting device that de-interleaves the decoded sub-images of each frame reformats the images for a display device. A 3D video may be encoded using a most advantageous interleaving format such that a preferred quality and compression ratio is reached. In one embodiment, the invention includes a display device that accepts data in multiple formats.
    Type: Grant
    Filed: June 29, 2020
    Date of Patent: March 22, 2022
    Assignee: Dolby Laboratories Licensing Corporation
    Inventors: Alexandros Tourapis, Walter J. Husak, Peshala V. Pahalawatta, Athanasios Leontaris
  • Patent number: 11276203
    Abstract: A system comprises an encoder configured to compress attribute information for a point cloud and/or a decoder configured to decompress compressed attribute information. Attribute values for at least one starting point are included in a compressed attribute information file and attribute correction values are included in the compressed attribute information file. Attribute values are predicted based, at least in part, on attribute values of neighboring points. The predicted attribute values are compared to attribute values of a point cloud prior to compression to determine attribute correction values. In order to improve computing efficiency and/or repeatability, fixed-point number representations are used when determining predicted attribute values and attribute correction values. A decoder follows a similar prediction process as an encoder and corrects predicted values using attribute correction values included in a compressed attribute information file using fixed-point number representations.
    Type: Grant
    Filed: November 25, 2020
    Date of Patent: March 15, 2022
    Assignee: Apple Inc.
    Inventors: Alexandros Tourapis, Valery G. Valentin, Fabrice A. Robinet, Khaled Mammou, Jungsun Kim, Yeping Su
  • Patent number: 11277619
    Abstract: Rate control techniques are provided for encoding an input video sequence into a compressed coded bitstream with multiple coding passes. The final coding pass may comprise final splices with non-overlapping frames that do not extend into neighboring final splices. A final splice in the final coding pass may correspond to at least one non-final splice in a non-final coding pass. A non-final splice may have overlapping frames that extend into neighboring final splices in the final coding pass. The overlapping frames in the non-final splice may be used to derive complexity information about the neighboring final splices. The complexity information about the neighboring final splices, as derived from the overlapping frames, may be used to allocate or improve rate control related budgets in encoding the final splice into the compressed coded bitstream in the final coding pass.
    Type: Grant
    Filed: June 18, 2020
    Date of Patent: March 15, 2022
    Assignee: Dolby Laboratories Licensing Corporation
    Inventors: Athanasios Leontaris, Alexandros Tourapis
  • Patent number: 11277636
    Abstract: Several improvements for use with Bidirectionally Predictive (B) pictures within a video sequence are provided. In certain improvements Direct Mode encoding and/or Motion Vector Prediction are enhanced using spatial prediction techniques. In other improvements Motion Vector prediction includes temporal distance and subblock information, for example, for more accurate prediction. Such improvements and other presented herein significantly improve the performance of any applicable video coding system/logic.
    Type: Grant
    Filed: May 12, 2020
    Date of Patent: March 15, 2022
    Assignee: Microsoft Technology Licensing, LLC
    Inventors: Alexandros Tourapis, Shipeng Li, Feng Wu
  • Publication number: 20220070493
    Abstract: A system comprises an encoder configured to compress attribute and/or spatial information for a point cloud and/or a decoder configured to decompress compressed attribute and/or spatial information for the point cloud. To compress the attribute and/or spatial information, the encoder is configured to convert a point cloud into an image based representation. Also, the decoder is configured to generate a decompressed point cloud based on an image based representation of a point cloud. In some embodiments, an encoder performs downscaling of an image frame prior to video encoding and a decoder performs upscaling of an image frame subsequent to video decoding.
    Type: Application
    Filed: November 10, 2021
    Publication date: March 3, 2022
    Applicant: Apple Inc.
    Inventors: Khaled Mammou, Yeping Su, Jungsun Kim, Valery G. Valentin, David W. Singer, Fabrice A. Robinet, Hsi-Jung Wu, Alexandros Tourapis
  • Patent number: 11252418
    Abstract: A multi-stage coding method includes receiving an input block of data for encoding and one or more previously coded samples associated with the input block. The input block is segmented into at least a first sub-region and a second sub-region. A prediction for the first sub-region is generated based on the one or more previously coded samples. Residual data for the first sub-region is obtained using the prediction for the first sub-region. A reconstruction of the first sub-region is generated using the residual data for the first sub-region and the prediction for the first sub-region. A prediction for the second sub-region is generated using the reconstruction of the first sub-region. Residual data for the second sub-region is obtained using the prediction for the second sub-region. The input block is encoded based in part on the residual data for the first region and the residual data for the second region.
    Type: Grant
    Filed: February 4, 2021
    Date of Patent: February 15, 2022
    Assignee: Apple Inc.
    Inventors: Krishnakanth Rapaka, Alexandros Tourapis, David William Singer
  • Patent number: 11252441
    Abstract: A system comprises an encoder configured to compress attribute information for a point cloud and/or a decoder configured to decompress compressed attribute information for the point cloud. To compress the attribute information, multiple levels of detail are generated based on an ordering of the points according to a space filling curve and attribute values are predicted. The attribute values may be predicted simultaneously while points are being assigned to different levels of detail. A decoder follows a similar prediction process based on level of details. Also, attribute correction values may be determined to correct predicted attribute values and may be used by a decoder to decompress a point cloud compressed using level of detail attribute compression. In some embodiments, attribute correction values may take into account an influence factor of respective points in a given level of detail on attributes in other levels of detail.
    Type: Grant
    Filed: January 29, 2021
    Date of Patent: February 15, 2022
    Assignee: Apple Inc.
    Inventors: Alexandros Tourapis, Jungsun Kim, Valery G. Valentin, Fabrice A. Robinet, Yeping Su, Khaled Mammou
  • Patent number: 11240515
    Abstract: Video coding schemes may include one or more filters to reduce coding artifacts and improve video quality. These filters may be applied to decode video data in a predetermined sequence. The output from one or more of these filters may be selected for different images, blocks, or sets of video data and then copied and/or routed to a display or a buffer storing reference data that is used to decode other video data in a data stream. Providing the ability to select which filter output is used for display and as a reference may result in better video quality for multiple types of video data. The filters that are selected for display and for reference may be different and may vary for different images, blocks, and data sets.
    Type: Grant
    Filed: February 4, 2013
    Date of Patent: February 1, 2022
    Assignee: Apple Inc.
    Inventors: Alexandros Tourapis, Athanasios Leontaris
  • Publication number: 20220005228
    Abstract: A system comprises an encoder configured to compress attribute information and/or spatial for a point cloud and/or a decoder configured to decompress compressed attribute and/or spatial information for the point cloud. To compress the attribute and/or spatial information, the encoder is configured to convert a point cloud into an image based representation. Also, the decoder is configured to generate a decompressed point cloud based on an image based representation of a point cloud.
    Type: Application
    Filed: September 3, 2021
    Publication date: January 6, 2022
    Applicant: Apple Inc.
    Inventors: Alexandros Tourapis, Khaled Mammou, Yeping Su, Fabrice A. Robinet, David W. Singer
  • Publication number: 20210400273
    Abstract: Improved video coding and decoding techniques are described, including techniques to derive quantization step sizes adaptively with quantization step size table templates. Quantization techniques described provide finer-grained control over quantization with a more flexible quantization step size especially at higher degrees of quantization. This may result in improved overall compression quality. Other coding parameters, such as in-loop filtering parameters, may be derived based on the more flexible quantization parameters.
    Type: Application
    Filed: April 19, 2021
    Publication date: December 23, 2021
    Inventors: Krishnakanth RAPAKA, Jaehong CHON, Alexandros TOURAPIS, David W. SINGER
  • Patent number: 11202098
    Abstract: A system comprises an encoder configured to compress attribute and/or spatial information for a point cloud and/or a decoder configured to decompress compressed attribute and/or spatial information for the point cloud. To compress the attribute and/or spatial information, the encoder is configured to convert a point cloud into an image based representation. Also, the decoder is configured to generate a decompressed point cloud based on an image based representation of a point cloud. In some embodiments, an encoder performs downscaling of an image frame prior to video encoding and a decoder performs upscaling of an image frame subsequent to video decoding.
    Type: Grant
    Filed: July 5, 2019
    Date of Patent: December 14, 2021
    Assignee: Apple Inc.
    Inventors: Khaled Mammou, Yeping Su, Jungsun Kim, Valery G. Valentin, David W. Singer, Fabrice A. Robinet, Hsi-Jung Wu, Alexandros Tourapis
  • Patent number: 11202078
    Abstract: A system comprises an encoder configured to compress attribute information for a dynamic point cloud and/or a decoder configured to decompress compressed attribute information for a dynamic point cloud. The dynamic point cloud may include multiple versions of the point cloud at multiple moments in time Attribute values for the point cloud may be compressed at a reference frame using an intra-prediction process and may be compressed at one or more reference frames using an inter-prediction process that takes advantage of temporal relationships between different frames (e.g. versions) of the dynamic point cloud at the different moments in time.
    Type: Grant
    Filed: September 24, 2020
    Date of Patent: December 14, 2021
    Assignee: Apple Inc.
    Inventors: Alexandros Tourapis, Jungsun Kim, Khaled Mammou, Liviu Traian Christian Tulvan, Marius Preda
  • Patent number: 11196988
    Abstract: Techniques for encoding video with motion compensation include a compressed bitstream syntax that includes a list of all motion prediction reference frames without distinguishing between short-term reference frame and long-term reference frames. The list of reference frames may be provided in a slice header and may apply to encoded data video data within the corresponding slice. The list may be prefaced with a single number indicating the total number of reference frames. In an aspect delta POC reference numbers may be encoded with a flag indicating the sign of the delta POC when the absolute value of the POC is not equal to zero. In another aspect, a flag may be encoded for every reference frame indicating if POC information should be used when scaling prediction references, and a weighting parameter may be included when POC information should be used.
    Type: Grant
    Filed: October 30, 2019
    Date of Patent: December 7, 2021
    Assignee: Apple Inc.
    Inventors: Alexandros Tourapis, Jungsun Kim, Krishnakanth Rapaka, David W. Singer
  • Publication number: 20210377547
    Abstract: A method of adaptive chroma downsampling is presented. The method comprises converting a source image to a converted image in an output color format, applying a plurality of downsample filters to the converted image and estimating a distortion for each filter chose the filter that produces the minimum distortion. The distortion estimation includes applying an upsample filter, and a pixel is output based on the chosen filter. Methods for closed loop conversions are also presented.
    Type: Application
    Filed: August 17, 2021
    Publication date: December 2, 2021
    Inventors: Alexandros Tourapis, Yeping Su, David W. Singer, Hsi-Jung Wu
  • Publication number: 20210377565
    Abstract: Sampled data is packaged in checkerboard format for encoding and decoding. The sampled data may be quincunx sampled multi-image video data (e.g., 3D video or a multi-program stream), and the data may also be divided into sub-images of each image which are then multiplexed, or interleaved, in frames of a video stream to be encoded and then decoded using a standardized video encoder. A system for viewing may utilize a standard video decoder and a formatting device that de-interleaves the decoded sub-images of each frame reformats the images for a display device. A 3D video may be encoded using a most advantageous interleaving format such that a preferred quality and compression ratio is reached. In one embodiment, the invention includes a display device that accepts data in multiple formats.
    Type: Application
    Filed: June 29, 2020
    Publication date: December 2, 2021
    Applicant: Dolby Laboratories Licensing Corporation
    Inventors: Alexandros Tourapis, Walter J. Husak, Peshala V. Pahalawatta, Athanasios Leontaris
  • Patent number: 11190749
    Abstract: Stereoscopic images are subsampled and placed in a “checkerboard” pattern in an image. The image is encoded in a monoscopic video format. The monoscopic video is transmitted to a device where the “checkerboard” is decoded. Portions of the checkerboard (e.g., “black” portions) are used to reconstruct one of the stereoscopic images and the other portion of the checkerboard (e.g., “white” portions) are used to reconstruct the other image. The subsamples are, for example, taken from the image in a location coincident to the checkerboard position in which the subsamples are encoded.
    Type: Grant
    Filed: June 16, 2020
    Date of Patent: November 30, 2021
    Assignee: Dolby Laboratories Licensing Corporation
    Inventors: Walter J. Husak, David Ruhoff, Alexandros Tourapis, Athanasios Leontaris
  • Patent number: 11190780
    Abstract: Techniques for selecting a coding mode for an image coding process are described. Coding modes can be selected through a coding mode transition state machine, a re-quantization process, selection of an optimal transform size, by skipping some quantization parameters, or by performing motion search.
    Type: Grant
    Filed: February 10, 2020
    Date of Patent: November 30, 2021
    Assignee: GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP., LTD.
    Inventors: Alexandros Tourapis, Yan Ye
  • Patent number: 11184613
    Abstract: An encoder system may include an analyzer that analyzes a current image area in an input video to select a transform. A selectable residue transformer, controlled by the analyzer, may perform the selectable transform on a residue image generated from the current image area and a predicted current image area, to generate a transformed residue image. An encoder may encode the transformed residue image to generate output data. The analyzer controls the encoder to encode information to identify the selectable transform and to indicate that the selectable transform for the current image area is different from a transform of a previous image area of the input video. A decoder system may include components appropriate for decoding the output data from the encoder system.
    Type: Grant
    Filed: March 18, 2020
    Date of Patent: November 23, 2021
    Assignee: Apple Inc.
    Inventor: Alexandros Tourapis